Many types of theft prevention apparatus for vehicles are known and presently used. These may be divided into two general categories, mechanical and electronic. The mechanical devices, such as steering wheel or brake locks prevent normal operation of a vehicle but suffer from the disadvantage that they can readily be broken and thus rendered ineffective by the application of a suitable force.
Electrical theft prevention devices, such as ignition switches and concealed electrical switches which interrupt the supply of battery current to the ignition coil and thus to the spark plugs for example, have gained substantial popularity. They too, however, may be overcome by a sufficiently clever thief possessing sufficient knowledge to electrically bypass the electrical switch. For this reason electrical theft prevention devices have not been entirely successful.
While it is acknowledged that it is nearly impossible to prevent theft of a vehicle in all cases, an electronic device which could deter thieves by requiring at least a significant amount of time and a non-trivial amount of skill to be bypassed is certainly needed.
The present invention seeks to provide an electronic theft prevention device for vehicles which overcomes the disadvantages of prior art devices and is not subject to electrical bypass or deactivation merely by means of the application of brute force or the connection of an external bypass wire.